<p>Although the candidate promised both to cut taxes and
improve services, he failed to keep either of them after
the election.
(A) Although the candidate promised both to cut taxes
and improve services, he
(B) The candidate, having promised both to cut taxes
and improve services,
(C) Although the candidate made promises both to cut
taxes and improve services, he
(D) Having promised, first, to cut taxes and, second,
to improve services, the candidate
(E) The candidates promises were both to cut taxes
and improve services, he</p>
<p>I clearly know why the answer is C, but aren't all the answers wrong because its suppose to be both (to cut taxes) and (to improve services).</p>
<p>both...and is not parallel on either sides of the sentence</p>
<p>With C the sentence becomes:</p>
<p>[Although the candidate made promises both to cut
taxes and improve services, he] failed to keep either of them after
the election.</p>
<p>Your question is “Shouldn’t it be?”</p>
<p>[Although the candidate made promises both to cut
taxes and improve services, he] failed to keep [both] of them after
the election.</p>
<p>The repeated use of “both” is at best awkward.</p>
<p>That said, the phrasing with “failed to keep either of them” adds a subtle meaning to the candidate’s lack of action that “both” does not. The writer is implying that it would have meant something if the candidate kept at least one of the promises.</p>
<p>There’s an equivalent sentence with the emphasis – “this is a candidate that doesn’t even do at least half of what he promises!”</p>
<p>[Although the candidate made promises both to cut
taxes and improve services, he] kept neither of them after
the election.</p>
<p>I think OP is actually asking shouldn’t C instead contain [to] like so: </p>
<p>Although the candidate made promises both to cut
taxes and [to] improve services, he failed to keep either of them after
the election.</p>
<p>I think OP has a point, and it is more proper to have the second [to] in the first clause. However, even without it, C is still the best answer out of all the choices.</p>
<p>yes, ttparent you understood my question. </p>
<p>So C is just the Best answer out of all the other ones?</p>
<p>I missed the point of your initial question. Sorry about that.</p>
<p>The second preposition is optional, and, more often than not, unnecessary. So (C) is the correct choice and not because it’s a compromise</p>
<p>You may want to take a look at the rules for using (or not repeating) prepositions in a list.</p>
<p>See:</p>
<p>When using a preposition in a list of items, the preposition only needs to be used once.</p>
<p>[Parallelism</a> With Prepositions Grammar Rules - Grammarly Handbook](<a href=“http://www.grammarly.com/handbook/sentences/parallelism/2/parallelism-with-prepositions/]Parallelism”>http://www.grammarly.com/handbook/sentences/parallelism/2/parallelism-with-prepositions/)</p>